Microphone plug



Nov. 24, 1936. E. M. FOSTER MICROPHONE PLUG Filed April 1'7, 1935 INVENTOR I [warm/M15315? BY I ATTORNEY Patented Nov. 24, 1936 UNITED STATES PATENT OFFICE MICROPHONE PLUG Application April 1'7,

3 Claims.

This invention relates to microphone structures and support stands and has particular relation t'o means for locking the microphone to .the support stand.

It is the usual practice to mount a microphone unit on a standard by means of a removable jack connection but it has been found that where the microphone and stand are placed in public places such as theater lobbies, on stages, and the like, the microphones are oftentimes stolen. It is just a matter of a moment for a thief to jerk the microphone off its stand, conceal it about his person and walk away. In fact, the microphone may be removed from the stand of the prior art in a single motion While the thief is walking past the microphone.

It is therefore a primary object of my invention to provide a microphone support stand which will deter thieves from stealing a microphone from a stand.

' Another object of my invention is to provide a means for locking a microphone to a stand in such a manner that a thief in attempting to remove a microphone would make a suflicient number of motions and take sufiicient time in removing the microphone that he would be observed, and yet permit an authorized individual to remove the microphone without undue loss of time.

Another object of my invention is to provide positive locking means for locking the microphone to a support standard.

A feature or advantage of my invention is that positive electrical connections are provided which prevent rattling in the pick up circuit. Furthermore, a connection of this kind is not likely to be jerked apart accidentally.

Other and further features and objects of my invention will be more apparent to those skilled in the art upon a consideration of the accompanying drawing and following specification, wherein is disclosed several exemplary embodiments of the invention, with the understanding, however, that such changes may be made therein as fall within the scope of the appended claims without departing from the spirit of the invention.

In said drawing:

Figure l is a view in elevation of a microphone and plug connection embodying my invention.

Figure 2 is a view in section of the end of the standard adapted to receive the microphone and plug connection shown in Figure 1.

Figure 3 is a partial view in elevation of another plug connection for a microphone con- 55 structed according to my invention.

1935, Serial No. 16,786

Figure 4 is a view in section of the end of a microphone support standard constructed according to another embodiment of my invention and adapted to engage the plug of Figure 3.

Figure 5 is a partial view in elevation of the end of the standard shown in Figure 4.

Figure 6 is a partial view, partly in elevation and partly in section, of a microphone plug constructed according to another embodiment of my invention.

Figure 7 is a view, partly in section and partly in elevation, of the end of a standard which will engage the plug shown in Figure 6 as constructed according to another embodiment of my invention; and

Figure 8 is a view in section taken along the line 8-8 of Figure 6.

Referring now to the drawing:

There is shown at H] generally a microphone such as is used with radio broadcasting systems, public address systems and the like. These microphones ordinarily employ the plug and jack connections shown in Figures 1 and 2 and including in the plug a barrel II and insulated button l2 and utilizing the jack portion which consists of the tubular standard 13 threaded at its upper inner wall to receive a thimble M. The thimble M has a bore I6 leading longitudinally therethrough of such diameter as to receive the barrel H of the plug. The thimble M has a downwardly extending strap ll which affords means for mounting a spring clip 18. The clip I8 is provided with a latch l9 to engage the post [2 of the plug and with a binding post 2| to furnish means for electrically connecting a lead to the clip. The cylindrical standard, the thimble l4, and the barrel of the plug form the other electrical conductor for the circuit.

One means of locking the plug within the thimble M is to employ the thread 23 formed at the base of the barrel I l of the plug and provides the thimble M with a female thread 24 to engage the male thread 23 in connecting the microphone to the standard. The plug is inserted in the thimble and then rotated several times as tocause the thread 23 to be threaded into the thread 24. It is apparent that a thief, in order to remove the microphone, must rotate the microphone several times. Ordinarily, the thief would not realize that the microphone could be removed in this manner and if he does take the time to remove the microphone, his motion in doing so would attract the attention of attendants an permit them to stop the thief before he had completely removed the microphone.

In some instances where the microphone is not well watched, a device, such as shown in Figures 3, 4, and 5, may be employed. The plug Ha is provided with a recess l and a set screw 26 is threaded to the wall of the thimble Ma and is so located that when the plug has been threaded into complete engagement, the recess l5 of the plug coincides with the point of the set screw and the set screw may be tightened down to engage the recess to prevent rotation of the plug. The head 26a of the set screw 26 is of peculiar shape, as for instance the triangular shape shown, so that a special wrench is needed to tighten and loosen the set screw and the head of the set screw is surrounded with a boss 28 Which prevents the set screw from being rotated by means of a pliers or the like.

In some extreme cases a device, such as shown in Figures 6, 7, and 8, may be employed. In this device the microphone face is provided with a lug 3| having a slotted recess 32 in the under side of the projecting portion of the lug. A similar lug 33 is provided as a part of the thimble I429. The lug 33 is provided with a vertical bore at its outer end which is coaxial with the slot 32 of lug 3| and the cylinder 34 of an ordinary tumbler lock is placed in the vertical bore of the lug 33. The rotating portion of the cylinder is provided with a shaft 36 and a lug 31, and in looking the microphone to the standard, the key 38 is rotated to the unlocked position and the plug inserted in the standard. At the same time that the plug is finally inserted into the standard, the cam 3? slides into the slotted recess 32. The key 38 is then rotated 90 to cause the cam to engage in an offset portion 32a of the recess 32 to lock the cam in the recess. The key is then removed and. in this way the microphone is locked to the standard in such a way that it cannotbe removed. In this manner, the microphone may be positively locked to the standard and cannot be removed by any unauthorized individual.

It is apparent that in one form of my invention I have provided a locking device which will deter items thieves from stealing the microphone. In another embodiment of the invention I have provided a locking mechanism which would offer considerable difiiculty to unauthorized removal of the microphone. In the third embodiment of my invention I have provided a locking mechanism which would prevent an unauthorized individual from stealing the microphone unless the microphone was forcibly removed .by means of tools.

Modifications of my invention may be made by 1 those skilled in the art and such modifications may be made without departing from the spirit and scope of the invention as set forth in the appended claims.

I claim as my invention:

,1. A microphone, a microphone support including a jack in the end of the support and means for locking the microphone to the support to discourage theft thereof comprising cooperative threads on the jack and microphone.

2. In combination a microphone, a standard for supporting the microphone, means for engaging the microphone on the standard and for electrically connecting the microphone to the standard comprising a plug'on the microphone and a jack in the standard, the jack having a thimble adapted to receive the plug, and means for locking the microphone on the standard comprising female threads on the thimble and male threads on the barrel of the plug.

3. Locking means including, in combination a microphone including a base, a standard for supporting the microphone including a pipe mem- 

